Development of applications of CSF-1 and IL34 in livestock

Macrophages are large white blood cells that are the first line of defense against pathogens, but also contribute to much of the pathology of infectious and inflammatory disease. Macrophages are also the body's cellular waste disposal system, are needed for wound healing and for many aspects of normal development. Our hypothesis is that two growth factors, macrophage colony-stimulating factor (CSF-1) and interleukin 34 (IL34) act through a common receptor (the CSF-1 receptor) to promote the production, migration and function of macrophages, and in turn, the macrophages are needed for the normal process of organ formation and overall growth in the embryo as well as maturation of the immune system. To utilise these proteins in livestock, we need to reduce the cost of manufacture to a level where they can be cost-effective. Although the cost of production is less crucial for proteins that could be used in human therapy, it is nevertheless a substantial restraint on the application of products like G-CSF and interferon. In this project, we aim to use transgenic chickens to produce the chicken and pig CSF-1 and IL34 proteins in egg white. The approach is harmless to the birds, because we have a technology in which the proteins are synthesised as a component of egg white, in the oviduct of laying hens. To move towards applying the technology, we need to establish practical ways of recovering the expressed proteins from eggs on a large scale. Assuming we are successful, we will then be in a position to test whether the CSF-1 and IL34 proteins are effective in large animals, and to apply the technology to other important therapeutic molecules.

Macrophages are key cells involved in innate immunity and homeostasis. Their production is controlled by two proteins, CSF-1 and IL34, that bind to different regions of a common receptor, the CSF-1 receptor. We hypothesise that the administration of these proteins to livestock could enhance their growth and accelerate the maturation of their immune systems and we have entered into a partnership with Pfizer Animal Health to develop these potential applications. For such applications to be practical in livestock, we would need to make large amounts of the proteins cheaply. To achieve this objective, we propose to make the proteins using transgenic hens, in which the proteins are expressed specifically in the oviduct as a compenent of egg white and can be recovered from eggs. The practical production of proteins in hens requires the optimisation of a practical approach to purification of untagged proteins from that source. In this project, we will make a series of transgenic lines in which various forms of pig and chicken CSF-1 and IL34 are produced in eggs. Whilst the lines are being made, we will develop purification protocols using an existing transgenic line expressing human interferon, and we will develop antibody reagents and assays that will enable us to test the impact of administering the recombinant proteins to chickens and pigs.

WHO WILL BENEFIT FROM THIS RESEARCH? This project bridges fundamental basic science and applied science. The Scientific Community will benefit from an increased knowledge of the fundamental developmental biology of the innate immune system. The Industry and General Public will benefit from improved poultry and pig production. It is envisaged that treatment with CSF1 and IL34 could have impact on both meat and egg production. Pigs and poultry are major livestock industries, a major source of protein in the UK and especially important to the third world. Even small changes in productivity and/or disease resistance will have very large economic impact. The further development of a new approach to making therapeutic proteins in eggs will make it practical to apply such proteins in veterinary medicine and livestock production, where cost would otherwise be prohibitive. It will also potentially reduce the cost of such therapeutic agents in human medicine (an avenue that will be explored in additional projects). HOW WILL THEY BENEFIT FROM THIS RESEARCH? Scientific community: This project may yield new insights and players involved in the genetic and developmental control of innate immunity and the link between immunity and normal development and growth. Broadening the knowledge base for basic vertebrate immunology research is particularly valuable given the different outcomes in the arms race between hosts and pathogens and the potential for zoonotic infections Industry: The project has already produced protected IP, which will be exploited to (a) produce recombinant proteins for application during chicken and pig production (and by extension, in mammalian and human clinical applications) (b) provide a rationale base for genetic selection of animals that vary in expression of the proposed regulators CSF1 and IL34 (c) provide a system for cost-effective production of other candidate therapeutic proteins (d) form the basis of a novel technology utilising the skill base available in egg production. Public: improvements in animal health and welfare and productivity, reduced costs of production for protein-based therapeutics. WHAT WILL BE DONE TO ENSURE THAT THEY HAVE THE OPPORTUNITY TO BENEFIT FROM THIS RESEARCH? Scientific community: Publication in the open access refereed scientific literature will be primary means for communicating our findings and hence potential benefits to the scientific community. We will also present our results at scientific meetings, including immunology meetings, i.e. not solely animal genetics meetings, in order that we engage with scientists for whom our approach is novel. Industry: We have an existing close partnership agreement with Pfizer Animal Health, and existing IP has been appropriately protected. The path for development of the IP is clear, and the proposed research will add value to that IP. Public: We (will) provide information about our research through our web site (with project-specific information), talks and discussion groups and direct interaction with the media. The Roslin Institute encourages clear and open communication and has a policy of promoting Public Engagement by means of interaction with the media, presentations, publications, exhibitions and schools activities. The Institute provides support for staff and students wishing to undertake such activities. The Roslin Institute has a Scientific Administrator who oversees both internal and external communication of the research performed at the institute. Track record: we have an excellent track record for facilitating the benefits of our research as outlined in greater detail in the Impact Plan attached to this proposal.